The present invention relates to accessory apparatus for circuit breakers and particularly to auxiliary switch apparatus for residential, molded case circuit breakers.
Commonly assigned U.S. Pat. Nos. 3,256,407 and 3,973,230, disclose residential molded case circuit breakers to which have been adapted auxiliary switch apparatus of the so-called "bell alarm" type. In accordance with this type of auxiliary switch, a change in switch condition is effected only when the circuit breaker is automatically tripped open, but not when the circuit breaker is opened manually via its external operating handle. Thus a bell alarm switch is utilized to control an external alarm circuit operating to alert personnel when a circuit breaker has tripped automatically in response to an abnormal circuit condition, e.g., overcurrent, ground fault and undervoltage, on the protected circuit; conditions requiring corrective measures. Since manual opening of a circuit breaker is normally not intended to call for corrective measures, no such alarm or signal is desired.
In certain applications however, it is desired to alert personnel when a circuit breaker is opened, regardless of whether it is tripped open or manually opened. The straightforward approach to achieving this function is to mechanically translate the opening movement of the breaker contacts into actuation of an auxiliary switch. In the case of residential molded case circuit breakers however, this straightforward approach is difficult to implement structurally.
It is accordingly an object of the present invention to provide improved auxiliary switch apparatus operating to produce an auxiliary switch actuation incident with the opening of a circuit breaker, regardless of how effected.
An additional object is to provide auxiliary switch apparatus of the above character which is compact, simple in construction, and reliable in operation.
Yet another object is to provide auxiliary switch apparatus of the above character which can be readily adapted to small residential, molded case circuit breakers with minimal modification to the breaker itself.
Other objects of the invention will in part be obvious and in part appear hereinafter.